冲旋钻井中钻柱纵向振动模型的建立与求解方法

Establishment and Calculation of the Model of Drill String Vertical Vibration during Percussion Drilling

根据动力学的基本理论分析认为 ,影响冲旋钻井中钻柱纵向振动的因素主要来自钻头与井底岩石的相互作用和冲击器的冲击作用。据此 ,在适当的简化条件下 ,利用弹性杆理论和单元法建立了在冲击器作用下的钻柱纵向振动的动力学模型 ,并采用数值差分法求解了这一模型 ,与旋转钻井情况下的结果进行了比较。为进一步研究钻柱在冲旋钻井中的实际运动规律和动力学性能 ,推广冲旋钻井技术在油气田中的应用奠定了基础。

According to the basic kinetic theories, the author thinks that there are two key factors which influence the vertical vibration of the drill string during percussion drilling. One is the interaction between bit and rock at the hole bottom. The other is the impact force of impactor. For this reason, under the proper simplifying conditions, the dynamic model of the drill string vertical vibration is established by using the theory of flexibility pole and cell method. And then, the model is solved by using numerical value difference method and is compared with the results under the conditions of rotary drilling. It establishes a foundation for further research of the practical movement rule and dynamic performance of drill string during percussion drilling and for its wide applications in oil and gas fields.